1. Field of the Invention
The present invention relates to a halogen-containing polyether and its use. More particularly, it relates to a halogen-containing polyether having good lubricating properties and its use as a lubricant.
2. Description of the Related Art
With the development of a magnetic recording medium, greater attention is paid the lubricity between a magnetic head and the surface of a magnetic layer of the recording medium.
Hitherto, as an effective lubricant for coating the magnetic recording medium, is a perfluoropolyether of the formula: EQU F--[CF(CF.sub.3)--CF.sub.2 --O].sub.n --C.sub.2 F.sub.5
(Krytox, a trade mark of DuPont, U.S.A.). However, the magnetic recording medium which uses this perfluoropolyether as a lubricant has unsatisfactory durability.
To form a lubricating layer of the perfluoropolyether on the magnetic layer, the perfluoropolyether should be diluted with a solvent to form a solution. As the solvent, trichlorotrifluoroethane alone can be used. However, trichlorotrifluoroethane has a low boiling point and easily evaporates. Therefore, it is very difficult to uniformly coat the lubricant on the surface of a magnetic recording medium, and as a result the evaporation loss is large.